Switching device for checking the closed position of a folding door

ABSTRACT

In the case of prison cell doors, strong room doors and the doors of safes and strongboxes the problem exists of protecting a switch fitted to the door or its frame and which as a result of the closing movement of the door releases an alarm signal from manipulations by unauthorized persons, for example the emission of a false signal by a prisoner when the cell door is open. A signal switch (3) with roller (16) is detachably fixed to door (1) and a stationary eccentric disc (4) which serves as the switch actuator is detachably fixed to frame (2). This mechanical switch device (3, 4, 16) is housed in a casing (5), whose base (6) is welded to door (1) and whose coverlike cap (7) is locked from the inside to casing base (6) by means of a cylindrical lock (8) in casing (5) and is consequently secured against raising therefrom. In the case of an optical switching device a transmitter (35) for infrared alternating light (41) and a receiver (36) with switching transistor (49) are arranged within the door (1) or frame (2) or vice versa. Only when the door (1) is closed is an infrared beam (41) passed through two aligned transmission beam ports (39, 40) in door (1) and frame (2) to receiver (36), thereby releasing an alarm signal.

The invention relates to a switching device for checking the closedposition of a folding door in which a signal is released due to theclosing movement of the door by means of a switch fitted to the door orits frame.

According to the invention this device can be used with equal advantageon all folding doors in which importance is attached to the reliablechecking of their closed state, e.g. prison cell doors, strong roomdoors, doors of strongboxes and safes.

In a known mechanical switching device of the type defined hereinbeforewhich is used for monitoring the closing of prison cell doors anelectrical signal circuit is closed by the closing movement of the celldoor and as a result an acoustic and/or optical alarm signal is givenfor the guard. In the case of this known device a signal switch with aspring-mounted tripping pin and constructed as a mechanical pushbuttonswitch is arranged inside the cell door and on closing the cell doormounted so as to swing by means of hinges on the door frame isautomatically forced inwards by a stationary switch actuating memberprovided on the frame and as a result closes the signal circuit.

However, this known switching device is not sabotage-proof because it ispossible for an unauthorised person such as a prisoner to operate theswitch with the cell door open, i.e. without closing the latter, bypressing the tripping pin inwards by hand or by locking the same, e.g.by means of a match, thereby releasing the door closing signal in orderto mislead the guard responsible for the particular prison wing in orderto prepare e.g. for a prison riot.

Live magnetic switch devices are also known for checking the closing ofa prison cell door in which a magnetic field is closed by the closingmovement of the cell door and consequently an alarm signal is released.However, such devices are not deception-proof against stray fields, i.e.they are also not sabotage-proof, because the magnetic field can also beclosed when the door is opened by an unauthorised person holding out apiece of iron, e.g. an iron plate which serves as a stray field and as aresult a misleading alarm signal can be given.

The object of the invention is to eliminate this disadvantage and itsproblem is therefore to provide a switching device of the type indicatedhereinbefore which is protected in an optimum manner against anymanipulations by unauthorised persons, i.e. it is sabotage-proof.

According to the invention this problem is solved by a switching deviceof the type defined hereinbefore wherein the switching device is madeinaccessible to unauthorised persons by covering members connected inundetachable, non-destructive manner to the door and frame.

A preferred embodiment of the invention can be constituted by amechanical switching device wherein the signal switch arranged on thedoor and the switching member for the actuation thereof arranged on theframe are located in a common casing comprising a casing baseundetachably and non-destructively connected to the door and a casingcap placed thereon and which is locked to the casing base by a safetylock arranged within the casing and detachably and non-destructivelyjoined to the casing cap from the inside and is therefore securedagainst raising by an unauthorised person, and wherein the casing basehas a locking stop covered by the casing cap for the lock bolt which italso covers, whilst the switch and its actuator only become accessibleafter raising the unlocked casing cap from the casing base.

According to a preferred embodiment of the switching device theswitching member comprises an eccentric disc provided on a pin connectedin undetachable and non-destructive manner with the frame, whilst amovable switch part of the switch is provided with a roller which runson the eccentric disc circumference on swinging the door.

According to another embodiment of the mechanical switching device thepin forming a pivot bearing for the casing base passes through a portionof said base which projects over the hinge side of the door and theeccentric disc is detachably and non-destructively fixed to a pinportion projecting into the casing, the switch is detachably andnon-destructively connected to a lower portion of the casing base andthe hollow pin serves at the same time to receive the switch cable whichpasses out of the inside of the frame and leads it to the switch.

Preferably the construction to be used of this switching devicecomprises the cross-sectionally substantially U-shaped casing basecomprises a carrier plate bent at right angles and a horizontallyextending band plate which is non-detachably and non-destructivelyconnected thereto, whilst one horizontal limb of the carrier plate formsa support stop for the casing cap which can be raised vertically upwardsfrom the casing base and a stop bracket whose horizontal limb serves asa locking stop is undetachably and non-destructively connected to thedownwardly projecting limb of the carrier plate.

According to another preferred embodiment of the switching device alower part of the pin is undetachably and non-destructively connected tothe frame by a pin shoe which spaces it from the frame and a cable ductundetachably and non-destructively connected therewith passes throughthe frame front wall, the pin shoe and a frame-side wall portion of thelower pin part.

Finally a preferred embodiment of the mechanical switching devicecomprises the vertically upwardly projecting limb of the bent carrierplate is provided with a horizontally extending window-like recess andthe stop bracket is provided on its horizontal stop limb with openingsfor the passage of the cable to the switch.

According to the invention a preferred embodiment of an opticalswitching device comprises an infrared alternating light transmitter anda receiver provided with a switching transistor associated with saidtransmitter and which are arranged within the door and/or frame or viceversa and are undetachably and non-destructively connected therewith, aswell as openings in the door and frame for the infrared beam which arealigned when the door is in the closed position and bulletproof glasssheets for covering the beam transmission openings arranged within thedoor and the frame and undetachably and non-destructively connectedtherewith from the outside.

According to a preferred embodiment of the switching device within theframe is provided a cable lead-in tube which is undetachably andnon-destructively connected therewith and a band plate arranged levelwith the transmitter and the receiver and connected undetachably andnon-destructively with the door has a plurality of openingscorresponding to the cable lead-in tube, whilst the front wall of thedoor has a window-like opening for the passage of the cable and which iscompletely covered by the band plate.

According to a preferred embodiment of the optical switching device thetransmitter and the receiver are set up for a plurality of beamtransmissions and the door and frame are provided with a number of beamtransmission ports covered by bulletproof glass sheets corresponding tothe number of beams.

Two embodiments of the switching device according to the invention aredescribed in greater detail hereinafter with reference to the attacheddrawings, wherein show:

FIG. 1 a mechanical switching device with the door closed in ahorizontal section along the line I--I of FIG. 2.

FIG. 2 the switching device according to FIG. 1 in a vertical sectionalong the line II--II of FIG. 1.

FIG. 3 the switching device according to FIG. 1 with the door open inthe same horizontal section as in FIG. 1.

FIG. 4 the switching device according to FIGS. 1 and 2 with the doorclosed in a vertical section along the line IV--IV of FIG. 2.

FIG. 5 an optical switching device with the door closed in a horizontalsection through the door and the frame.

FIG. 6 the cover of the beam transmission port in the door as Detail VIIof the switching device of FIG. 5 on a larger scale.

FIG. 7 a circuit diagram of the switching device of FIG. 5.

FIG. 8 the arrangement of beam transmission ports on the edge of thedoor for a switching device according to FIG. 5, but with an infraredradiation transmitter for a plurality of beams in a diagrammatic planview of the door edge.

In FIG. 1 the swinging door is 1 and the associated door frame 2. Door 1is mounted so as to swing outwards on frame 2 in the direction of therotation direction arrow A1 by means of a plurality of hinges not shownby reasons of clarity in FIG. 1. In FIG. 1 the door is in its closedposition and is e.g. a prison cell door, frame 2 being embedded in thecorridor-side cell wall and firmly anchored thereto. A signal switch 3located on door 1 and a switching member 4 provided for the actuationthereof on frame 2 are located in a common casing 5 which essentiallycomprises a casing base 6 located on door 1 and a cover-like casing cap7 which can be placed thereon (cf also FIGS. 2 and 4). Casing base 6 iswelded at several points to the front of door 1, i.e. it cannot beremoved without damaging or destroying parts of door 1. Such aconnection of parts, designated hereinafter as "undetachably andnon-destructively" is of decisive importance for the protection of theswitching device against manipulations by an unauthorised person, namelya prisoner. Casing 5 also contains a safety lock 8, constructed in thiscase as a cylindrical lock and which serves to internally lock casingcap 7 to casing base 6, which prevents unauthorized raising of cap 7from base 6. Since, due to the locked casing cap 7, the cylindrical lock8 is not accessible to unauthorised persons it can be detachablyconnected to casing cap 7 by means of a hexagonal nut 9. The rotor 10 ofcylindrical lock 8 is provided at the front with a key channel for theinsertion of a fitting flat key and has at its rear end a bolt 11 whichin its locking rotation position engages from below on a horizontallydirected limb 12 of a stop bracket 13 welded to the casing base 6 andthereby prevents any raising in a vertically upwards direction of casingcap 7 from casing base 6.

Switching member 4 for actuating the signal switch 3 is in this caseconstructed as an eccentric disc and by means of a set screw 14 isdetachably but non-rotatably fixed with respect to a verticallyextending pin 15 and is in turn welded to door frame 2. Axis A15 of pin15 coincides with the swivel axis of swinging door 1 and is thereforealso aligned with the door hinge axes. A roller 16 belonging to switch 3on swinging door 1 runs on the circumference of eccentric disc 4 and ispivoted on the free end of a switch lever 17, which is in turn pivotedat 18 in switch 3. Switch lever 17 is in continuous working connectionwith a contact stud 19 which is responsible for the actual switchingprocess, i.e. it closes the circuit for releasing an alarm signal. InFIG. 1, which shows the door in its closed position the signal circuitis closed, i.e. when door 1 is closed switch lever 17 is pressed by thestationary eccentric disc 4 via roller 16 against contact stud 19counter to the pressure of a spring which cannot be seen in FIG. 1,thereby closing the circuit. A special mechanism ensures that aftersupplying an alarm signal of given duration the signal circuit is openedagain, so that after some time the signal tone dies away again.

The substantially U-shaped casing base 6 shown in vertical section inFIG. 4 comprises a carrier plate 20 bent at right angles and ahorizontally extended band plate 21 welded thereto (cf FIGS. 2 and 4).Switch 3 which is screwed to plate 20 by means of two fastening screws22 (cf also FIG. 2) has three cable connections 23 to which areconnected the cables of the signal circuit system. The verticallydownwardly projecting limb 24 of the angular carrier plate 20 has awindow-like recess 25 for the passage of the cable from the inside ofdoor 1, whilst the horizontally directed limb 12 of the stop bracket 13welded to the carrier plate 20 is provided with two openings 26 for thepassage of two of these three cables to the two cable connections 23covered by the angle bracket limb 12.

The twice recessed pin 15 is hollow cylindrical (cf FIG. 2) and servesat the same time to carry the cable from the inside of frame 2 to switch3. For this purpose a cable lead-in duct 27 is also provided which iswelded from behind to the front wall 2a of frame 2 and passes throughthe latter, as well as a pin shoe 28 which spaces the pin 15 from frame2 and a frame-sidewall portion of the lower hollow cylindrical part 15aof pin 15 (cf also FIG. 4). Pin shoe 28 is welded to the front wall 2aof frame 2 and in turn the lower portion 15a of pin 15 is welded to thepin shoe 28 (cf also FIG. 4).

FIG. 2 shows how the casing cap 7 is unlocked from casing base 6 when anauthorised person using a key which fits cylindrical lock 8 turns thelock rotor and at the same time also the lock bolt 11 from the lockingrotation position into the unlocking rotation position indicated at 11'.During this unlocking process the downwardly pivoting lock bolt 11 isfreed from the horizontal limb 12 of stop bracket 13, after which thecover-like casing cap 7 can be raised vertically upwards from thecarrier plate 20 belonging to base 6 if previously a fastening screw 29which only serves to fix cap 7 is unscrewed from the horizontal limb 30of the angular carrier plate 20 and which serves as a support for cap 7.Stop bracket 13 welded to carrier plate 20 is provided with a recess 31on its horizontal limb 12 and this recess gives access to the two switchfastening screws 22. This can be gathered from FIG. 1 where theright-hand tab of the horizontal limb 12 is shown broken away in orderto show the switch lever 17 and cam follower 16 located thereunder. FIG.2 also clearly shows how the angular carrier plate 20 and plate 21welded to the bottom thereof form the casing base 6 which by weldingplate 20 to door 1 is undetachably and non-destructively connectedthereto, the shape and dimensions of cap 7 being adapted to base 6 whichreceives it (cf also FIG. 4). FIG. 2 also shows the twice recessedcylindrical pin 15 into whose lower hollow cylindrical part 15a issuesthe cable lead-in tube 27, whose central pin portion 15b passes throughplate 21 and to whose upper pin portion 15c, having the smallestdiameter, is detachably fixed eccentric disc 4 by means of clamping bolt14 which engages in an annular groove R15c of pin portion 15c. Pin 15which is hollow cylindrical from bottom to top in order to be able tosupply to switch 3 through pin 15 the cable carried in cable lead-intube 27, is closed at the bottom by a pin cover 32 fixed to pin 15 bymeans of a clamping bolt 33 engaging in an annular groove R15a of thelower pin portion 15a. A rectangular mounting plate 34 (cf also FIG. 1)ensures by the selection of its thickness the correct height position ofswitch 3 or its cam follower 16.

FIG. 3 shows door 1 together with casing 5 fixed undetachably andnon-destructively thereto and which contains the switching device swungin the direction of rotation arrow A1 by 180° into its open position.During the swinging of folding door 1 the roller 16 of switch lever 17which rolls on the fixed eccentric disc 4 has freed itself from disc 4,so that the outwardly pivoting switch lever 17 makes it possible for thecontact stud 19, under the pressure of its spring to pass leftwards outof the switch casing 3 in FIG. 3, thereby interrupting the signalcircuit. FIG. 3 also shows the approximately square mounting plate 34for switch 3, the three cable connections 23 and the two openings 26 ofstop bracket limb 12 on bracket 13. The front ends of cylindrical lock 8and its rotor or cylinder core 10 provided with key channel 10a arelocated at the rear with door 1 open.

FIG. 4 shows a vertical section of the switching device with door 1closed. The horizontally directed member 30 of angular carrier plate 20,which serves as a support stop for casing cap 7, comprises a stripwhich, above the cable passage window 25 is welded to the vertical platelimb 24 of carrier plate 20 (cf also FIG. 2). FIG. 4 again shows thecylindrical lock 8 with fastening nut 9 and rotor 10, the stop bracket13 which is partly covered by cylindrical lock 8, eccentric disc 4partly covered by switch 3, plate 21 welded at the bottom to thevertical limb 24 of carrier plate 20 and the three cable connections 23.FIG. 4 also clearly shows how pin 15 is spaced from frame 2 by pin shoe28 welded on the one hand to the front wall 2a of frame 2 and on theother to pin portion 15a and how it is undetachably andnon-destructively connected therewith. FIG. 4 also shows how the cablescan be passed from the inside of frame 2 through the cable lead-in tube17 welded to the back of the frame front wall 2a and subsequentlythrough the cavity of the hollow cylindrical pin 15 up to switch 3 orits cable connections 23.

FIG. 5 diagrammatically shows in a cross-section through door 1 andframe 2 a signal switching device actuated by means of infraredalternating light beams. Within door 1 is provided a transmitter 35 andwithin frame 2 a receiver 36 and these are screwed by two fasteningscrews 37 to a mounting plate 38 connected to door 1 or frame 2. Door 1and frame 2 are provided in each case with a beam transmission port 39or 40 for the passage of infrared beams from transmitter 35 to receiver36. When door 1 is closed (cf FIG. 5) the two ports 39 and 40 arealigned and only then can the receiver 36 receive the infrared beam 41from transmitter 35 and further process the same as will be explained ingreater detail hereinafter relative to FIG. 7. The switching device isprotected against sabotage by bullet-proof glass sheets 42 of which FIG.5 only shows the sheet belonging to port 39, i.e. associated withtransmitter 35. The way in which the bulletproof glass panes 42 arearranged and fixed to the lateral wall of door 1 or frame 2 will bedescribed hereinafter relative to FIG. 6. A band plate 21a is welded todoor 1 and at the same height a cable lead-in tube 27a is welded toframe 2, both of whose height corresponds to transmitter 35 or receiver36. A plate 43 welded to the front wall 2a of frame 2 has an opening 44aligned with the opening of the cable lead-in tube 27a. Openings 45 and46 at the same height are provided in plate 21a and correspond to theopening 44 of plate 43 and therefore also with the internal diameter ofcable lead-in tube 27a. Two cables of the cable system indicatedsymbolically by thick lines in FIG. 5 are passed through the cablelead-in tube 27a and the following openings 44, 45 and 46 to thetransmitter 35, whilst also traversing a recess 47 in plate 21a and awindow opening 48 in front wall 1a of door 1, the latter being coveredcompletely by the plate 21a welded to door 1.

In FIG. 6 the beam transmission port 39 of door 1 is completely coveredfrom the inside by the bulletproof glass sheet 42. A retaining ring 49which serves to fix the bulletproof sheet 42 is fixed from the inside todoor 1, e.g. by means of screws. Port 39 has on the outer door wallsurface 1s only a relatively small internal diameter which is adequatefor the passage of the infrared beams and which widens conically in therearward direction. This construction of the transmission port 39facilitates the assembly of transmitter 35 (cf FIG. 5) with a view to acompletely satisfactory beam transmission, because as a result thereofthe accuracy of adjustment can be correspondingly reduced. In the sameway port 40 in frame 2 (cf FIG. 5) associated with receiver 36 iscovered from the inside by a bulletproof glass sheet 42.

FIG. 7 shows a circuit diagram for the switching device of FIG. 5. Thebeam 41 passes from transmitter 35 in door 1 to receiver 36 in frame 2.Beam 41, which is in the form of infrared alternating light beams with apulse repetition frequency of approximately 2 kHz switches a switchingtransistor 49 provided in receiver 36 when door 1 is in the closedposition and this signal is processed by the alarm system. The signalfrom transistor 49 is designated by 50 in FIG. 7. The mains voltagesystem is indicated by a positive wire 51 and a negative wire 52 and canfor example be designed for a voltage of 24 V. If door 1 is open theinfrared alternating light passage is interrupted, because the two beamtransmission ports 39 and 40 (cf FIG. 5) are no longer aligned, so thatbeam 41 can no longer reach receiver 36. Thus, with door 1 opentransistor 49 is blocked and can therefore no longer supply a signal vialine 50 to the alarm system.

According to FIG. 8 the transmitter and the receiver can be set up insuch a way that a plurality of sharply focussed beams can be transmittedby the transmitter or received by the receiver. Therefore the lateraldoor wall and the frame wall associated therewith contain a plurality ofbeam transmission ports which are aligned in pairs with the door closed.

It is advantageous to provide these ports on the horizontally directedupper edge of the door or frame because they are then difficultyaccessible to unauthorised persons. FIG. 8 shows a series of ports 39arranged on the upper horizontal edge of door 1. As the individual beamsare closely focussed the transmission ports 39 can have a very smallinternal diameter. Of the five ports shown in FIG. 8 in this case beamsfrom the transmitter only strike three ports 39, whilst the other twoports 39' are only blind ports, i.e. never PG,15 receive beams. Due tothe irregular arrangement of active ports 39 and blind ports 39' in theopening row and/or by irregular distribution of their positions on thedoor edge surface the possibility of sabotage by manipulation on thepart of unauthorised persons is further reduced. The ports 40 arrangedin the upper horizontal frame edge are obviously arranged as regardsposition and active or blind characteristics in exactly the same way asthe active ports 39 and blind ports 39'.

We claim:
 1. A switching device for checking the closed position of aswinging door mounted in a frame, the device being of the type in whicha signal is produced by the closing movement of the door relative to theframe comprisinga signal switch mounted on the door; a switch actuatingmember attached to the frame; and a housing on said door substantiallytotally enclosing said switch and said member, said housing includingahousing base fixedly and undetachably attached to the door, a housingcap releasably attachable to said base to form a closed volume, saidbase having a locking stop member formed thereon in said closed volume,and a lock mounted on said cap, said lock having a lock bolt engageablewith said locking stop to retain said cap in its attached position onsaid base when said lock is in the locked position; said switch andswitch actuating member being accessible only when said lock is operatedto its unlocked position and said cap is released from said base.
 2. Aswitching device according to claim 1 wherein said switching actuatingmember comprisesa pin undetachably connected to said frame in coaxialalignment with the hinge axis of the door, and a disk eccentricallymounted on said pin; and wherein said switch includes a switchablecontact set fixedly attached to said base, an arm movably mountedrelative to said contact set, means interconnecting said arm and contactset to operate the contact set when the arm is moved, and a rollermounted on said arm and rolling on said disk whereby movement of saiddoor and base relative to said frame causes actuation of said contactset.
 3. A switching device according to claim 2 wherein said baseprojects across the pivot axis for the door and said pin passes throughand forms a pivot bearing for said base, said pin being hollow and alsoforming a cable conduit for electrical conductors extending between saidswitching and said frame.
 4. A switching device according to claim 1wherein said base is generally U-shaped in cross-section and includes acarrier plate extending perpendicular to one wall thereof and ahorizontally extending band plate non-detachably connected to said wall,a horizontal limb of said carrier plate forming a support stop for saidcap so that said cap can be lifted vertically therefrom, said base alsoincluding a bracket having a horizontal member defining said lockingstop.
 5. A switching device according to claim 3 and including a pinshoe nondetachably connected to said frame and supporting said pin, andmeans defining a cable duct fixedly attached to and extending throughsaid frame and pin shoe and engaging said pin.
 6. A switching deviceaccording to claim 4 wherein said carrier plate and said support stopinclude means defining access openings for passage of conductors to saidswitch.
 7. A switching device for checking the closed position of aswinging door mounted in a frame, the device being of the type in whicha signal is produced by the closing movement of the door relative to theframe comprisingan infrared transmitting device in one of the door andframe; an infrared receiving device in the other of the door and framefor producing a distinguishable signal when infrared energy is received;circuit means including a switching transistor coupled to saidtransmitting device for selectively activating said receiving device toproduce an alarm-activating signal in the presence of infrared energy;means defining a plurality of ports in each of said door and frame topermit passage to infrared energy therethrough, said ports being alignedin pairs when the door is closed,said transmitting device being arrangedto project energy and said receiving device being arranged to receiveenergy through at least one but less than all of said pairs of ports; apane of bullet proof glass transparent to infrared energy covering eachof said ports, each said pane being undetachably fastened to itsassociated port; conductor means for interconnecting said transmittingand receiving devices; and means undetachably fastened to said door forproviding a conduit for said conductor means when said door is closedand open and to inhibit tampering with said conductor means.